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author | Pavel Emelyanov <xemul@openvz.org> | 2008-03-26 16:27:22 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2008-03-26 16:27:22 -0700 |
commit | 67727184f28c38d06013c6659560bb046c1d9f9c (patch) | |
tree | fce5871c7fe554e05aa61fcc2d2d86afe7befdbc /net/8021q/vlan.c | |
parent | 789e41e6f496022ac1639aaae38ea1943606a9d0 (diff) | |
download | linux-stable-67727184f28c38d06013c6659560bb046c1d9f9c.tar.gz linux-stable-67727184f28c38d06013c6659560bb046c1d9f9c.tar.bz2 linux-stable-67727184f28c38d06013c6659560bb046c1d9f9c.zip |
[VLAN]: Reduce memory consumed by vlan_groups
Currently each vlan_groupd contains 8 pointers on arrays with 512
pointers on struct net_device each :) Such a construction "in many
cases ... wastes memory".
My proposal is to allow for some of these arrays pointers be NULL,
meaning that there are no devices in it. When a new device is added
to the vlan_group, the appropriate array is allocated.
The check in vlan_group_get_device's is safe, since the pointer
vg->vlan_devices_arrays[x] can only switch from NULL to not-NULL.
The vlan_group_prealloc_vid() is guarded with rtnl lock and is
also safe.
I've checked (I hope that) all the places, that use these arrays
and found, that the register_vlan_dev is the only place, that can
put a vlan device on an empty vlan_group.
Rough calculations shows, that after the patch a setup with a
single vlan dev (or up to 512 vlans with sequential vids) will
occupy approximately 8 times less memory.
The question I have is - does this patch makes sense, or a totally
new structures are required to store the vlan_devs?
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net/8021q/vlan.c')
-rw-r--r-- | net/8021q/vlan.c | 36 |
1 files changed, 23 insertions, 13 deletions
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c index c35dc230365c..694be86e4490 100644 --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -106,29 +106,35 @@ static void vlan_group_free(struct vlan_group *grp) static struct vlan_group *vlan_group_alloc(int ifindex) { struct vlan_group *grp; - unsigned int size; - unsigned int i; grp = kzalloc(sizeof(struct vlan_group), GFP_KERNEL); if (!grp) return NULL; - size = sizeof(struct net_device *) * VLAN_GROUP_ARRAY_PART_LEN; - - for (i = 0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++) { - grp->vlan_devices_arrays[i] = kzalloc(size, GFP_KERNEL); - if (!grp->vlan_devices_arrays[i]) - goto err; - } - grp->real_dev_ifindex = ifindex; hlist_add_head_rcu(&grp->hlist, &vlan_group_hash[vlan_grp_hashfn(ifindex)]); return grp; +} -err: - vlan_group_free(grp); - return NULL; +static int vlan_group_prealloc_vid(struct vlan_group *vg, int vid) +{ + struct net_device **array; + unsigned int size; + + ASSERT_RTNL(); + + array = vg->vlan_devices_arrays[vid / VLAN_GROUP_ARRAY_PART_LEN]; + if (array != NULL) + return 0; + + size = sizeof(struct net_device *) * VLAN_GROUP_ARRAY_PART_LEN; + array = kzalloc(size, GFP_KERNEL); + if (array == NULL) + return -ENOBUFS; + + vg->vlan_devices_arrays[vid / VLAN_GROUP_ARRAY_PART_LEN] = array; + return 0; } static void vlan_rcu_free(struct rcu_head *rcu) @@ -247,6 +253,10 @@ int register_vlan_dev(struct net_device *dev) return -ENOBUFS; } + err = vlan_group_prealloc_vid(grp, vlan_id); + if (err < 0) + goto out_free_group; + err = register_netdevice(dev); if (err < 0) goto out_free_group; |